In many portable electronic devices using a rechargeable battery cell, the device specification often requires that the battery be capable of being rapidly recharged in one hour. Often the user considers one hour to be too lengthy a delay and does require the battery in the device to be charged at even a faster rate. Thus, what has been deemed an "ultra-fast" charge of 15 minutes is often required to prevent both the inoperability of the device and any inconvenience to the user.
In order to use ultra charging with either nickel cadmium (nicad), nickel-metal hydride or lithium chemistry batteries, it is necessary that the battery charger have a wide dynamic range. This means that voltage and current regulation is capable of being controlled to a very high degree of resolution such as 25 millivolts or greater. Additionally, this package should be small having a high output power as well as the capability of being housed in an cigarette plug adapter using a direct current (DC) attachment for use with an automobile or the like.
Thus, the need exists for a recharging apparatus and method capable of regulation resolution for use with any one of the standard chemistry types of rechargeable battery cells. Moreover the device should be efficient and housed in a small transformerless package for ultra-charging in a DC to DC environment.